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1846/69 - first isolation
Friedrich Miescher, a Swiss physician, was the first man who isolated DNA from the nuclei of some white blood cells that he took from the pus of surgical wounds. -
1859 - Charles Darwin publishes "On The Origin of Species"
On his return to England after a five year scientific expedition in the Galapagos Islands, Darwin proposed a theory of evolution occurring by the process of natural selection, which he then worked on over the following 20 years. The Origin of Species was the culmination of these efforts and argued that the living things best suited to their environment are more likely to survive, reproduce and pass on their characteristics to future generations. -
1909 - DNA'S COMPONENTS AND STRUCTURE DETERMINATION
Phoebus Levene, a Russian-American biochemist, identified DNA components and proved its structure.
Although his conception was wrong: he didn't realize that the DNA molecule carried genetic information, he actually believed that proteins were the molecules of heredity.
He also thought that nucleotides were found in equal amounts in DNA molecules (TETRANUCLEOTIDES THEORY) -
1944 - the heritance molecule
Oswald Avery, a Canadian-American physicician and medical researcher, and his co-workers recognized DNA ad the molecule responsible for passing genetic characteristics. -
1949 - measurement of the four nitrogenous bases
Erwin Chargaff isolated DNA from different organism and measured the level of each of the four nitrogenous bases. -
1952 - Rosalind Franklin photographs crystallized DNA fibres
Rosalind Franklin, a British biophysicist and X-ray crystallographer, working with the scientist Maurice Wilkins, was able to produce two sets of high-resolution photographs of DNA fibres. Using the photographs, she calculated the dimensions of the strands and also deduced that the phosphates were on the outside of what was probably a double helical structure. -
1953 - the discovery of the DNA double helix
In the same year of Rosalind Franklin's breakthrough, American genetis James Watson and English physicist Francis Crick, built their model of "double helix" using metal scraps from the machine shop, based on Franklin's contribution. They published the first accurate model of the DNA molecule in April 1953. -
1962 - Watson, Crick and Wilkins receive the Nobel Prize
In 1962 Watson and Crick were awarded the Nobel Prize for Physiology or Medicine along with Maurice Wilkins.
Despite the fact that her photographs had been critical to Watson and Crick's solution, Rosalind Franklin was not honoured, as only three scientists could share the prize. She died in 1958, after a short battle with cancer. -
1996 - Dolly the sheep is cloned
Dolly the sheep was the first mammal to be cloned from an adult cell.
She was created by scientists working at the Roslin Institute (RI) in Scotland, from the udder cell of a six-year-old Finn Dorset white sheep. Cloning from adult cells is a difficult process and out of 277 attempts, Dolly was the only lamb to survive. She went on to live a pampered existence at the RI and was able to produce normal offspring. Following her death, she was stuffed and put on display. -
2002 – Mouse is the first mammal to have its genome decoded
In 2002, scientists took their next step and decoded the genome of the mouse. The achievement allowed them to compare, for the first time, the human genome with that of another mammal. Amazingly, it emerged that 90% of the mouse's genome could be aligned with the corresponding regions on the human genome. Both the mouse and human genome also contained around 30,000 protein-coding genes. These discoveries highlighted for the first time just how closely mammalian species were genetically related.
